[StBernard] Army Corps faulted on New Orleans levees

[Westley Annis]

Army Corps faulted on New Orleans levees 
Experts: Studies foresaw systemwide failure, safety review needed

By Joby Warrick and Peter Whoriskey
The Washington Post
Updated: 11:37 p.m. ET March 24, 2006


NEW ORLEANS - An organization of civil engineers yesterday questioned the
soundness of large portions of New Orleans's levee system, warning that the
city's federally designed flood walls were not built to standards stringent
enough to protect a large city. 

The group faulted the agency responsible for the levees, the Army Corps of
Engineers, for adopting safety standards that were "too close to the margin"
to protect human life. It also called for an urgent reexamination of the
entire levee system, saying there are no assurances that the miles of
concrete "I-walls" in New Orleans will hold up against even a moderate
hurricane.

"The ability of any I-wall in New Orleans to withstand . . . is unknown,"
said the American Society of Civil Engineers' External Review Panel, which
was appointed to oversee the Corps investigation of the levee system's
collapse during Hurricane Katrina.

The civil engineers group also rejected the explanation given by the Corps
that the system had failed because Katrina had unleashed "unforeseeable"
physical forces that weakened the flood walls. In a letter to Lt. Gen. Carl
A. Strock, the Corps' commander, the civil engineers cited three previous
Corps studies that predicted precisely the chain of events that caused the
city's 17th Street Canal flood wall to fail. The breach left much of central
and downtown New Orleans underwater.

"It appears that this information never triggered an assessment . . .
neither at the time of the design of the 17th Street Canal flood wall, nor
following its construction," the letter said.

Feds defend response to concerns
Corps officials said they had already taken steps to address problems
identified in the letter, starting with an effort to replace miles of
I-walls with sturdier structures. But agency officials insisted the Corps
was not solely to blame for weaknesses in the system.

"We have done the best things we could have done. We live here," spokeswoman
Susan J. Jackson said. During four decades of levee-building in New Orleans,
Jackson said, the agency frequently found its hands tied because of
restrictions imposed by budgets, by Congress or by local governments that
often failed to meet financial responsibilities to help build and maintain
the levees. Jackson added: "It was a question of who was going to pay, and
how much."

The American Society of Civil Engineers panel is one of three independent
teams investigating the failure of the New Orleans levees, and until now it
has been the most cautious in its public criticisms. The other investigating
teams quickly endorsed its findings.

"We agree that every single foot of the I-walls is suspect," said Ivor van
Heerden, leader of a Louisiana-appointed team of engineers. "When asked, we
have constantly urged anyone returning to New Orleans to exercise caution,
because the system now in place could fail in a Category 2 storm. It has
already failed during a fast-moving Category 3 storm that missed New Orleans
by 30 miles."

Two weeks ago, the Corps proposed a new theory for why the 17th Street Canal
flood wall collapsed on Aug. 29, despite never being overtopped by Katrina's
floodwaters. While previous investigations had pointed to weak soils beneath
the flood wall, new data suggested a combination of factors: First, the
force of rising floodwaters inside the canal bent the walls outward,
creating a small gap between the walls and their earthen foundation. Then,
water surged into the gap, pressing the walls further until they broke
through a layer of weak soil piled up against the sides. In effect, the
levee was sliced in half along its ridge.

Panel: Failure was predictable
Corps officials initially said they had never known a levee to fail this
way, and they suggested that no one could have predicted it. But the civil
engineers panel said yesterday that the failure was foreseen by the Corps'
own studies, dating to the mid-1980s. It said the Corps' failure to
anticipate the problem reflected an "overall pattern of engineering judgment
inconsistent with that required for critical structures."

Throughout the design process, the civil engineers said, the Corps
consistently failed to make the kinds of conservative judgments necessary
when working in an environment where the soils are notoriously unstable and
the stakes, as measured in human lives, are high.

"These findings present significant implications for current and future
safety offered by levees, flood walls and control structures in New Orleans,
and perhaps elsewhere," the letter to Strock said.

The civil engineers panel is due to release a formal report on its findings
in two weeks, but its members chose to send the letter to Strock separately,
citing the "gravity and potential impact" of their findings.

Whoriskey reported from New Orleans.

C 2006 The Washington Post Company

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URL: http://msnbc.msn.com/id/11987825/